McLeish was part of the successful Dons team that won 10 major trophies under Ferguson between 1978 and 1986, including the Uefa Cup Winners’ Cup and Super Cup, but saw the club struggle after their manager departed for Old Trafford.

The former Aston Villa boss says there will be an inevitable adaptation period for Moyes as his players get used to new methods and life after Ferguson, but is confident the new boss will be able to guide United through the transition.

“That bunch of boys [at Aberdeen] all had a strong winning mentality anyway. But what [Ferguson] gave us, he was just relentless,” he told Goal.

“His drive, relentless, relentless, relentless. So you couldn’t let up. I knew I was playing for my place in the team every single game. I wasn’t in fear of Sir Alex, I was in fear of losing my place in the team. And that’s what drove me, but he was the guy who was behind it driving me.

“Then when he left in ‘86 a lot of them breathed a sigh of relief ... ’Thank God he’s gone’, you know? Although one or two players had left I knew a lot of the boys who were delighted to see him gone would be the first ones to miss him. And I see that a little bit in Man United just now.

“Players can’t go on playing forever – although Ryan Giggs seems to be the exception to that rule! Maybe subconsciously some players have dropped a gear, it would be more of a psychological thing ... 'Phew, he’s not killing me every week’, you know?

“When you’ve got a cupboard full of trophies like him then every player’s going to listen. And that’s what I’m saying, they’ve probably just subconsciously dropped off a little, there’s an unintentional kind of drop off in terms of the foot on the gas.

“It’s not that Moysey cannot live up to it. Moysey could be the biggest shouter in the world, I could go in there and be the biggest shouter in the world, but it’s not the same. It won’t be the same voice as the one who has had 25 years of success. Inevitably there has to be an adjustment period when players get a new manager for the first time in many years. The players are clearly experiencing a transition this season but I have every confidence that David Moyes will lead them through this.”

And McLeish believes things will improve for United when Moyes brings in some new faces to consolidate the talent that he currently has at his disposal.

“I back Moysey to be successful," he added. "It’s easy for me to say that, Davie’s got to prove himself but I think he will.

“United will keep faith in him, and there’s no doubt that when he makes more signings of his own that things will change. If Moysey spends on players that are capable of playing for Man United then it will be completely different results than what we are seeing through this inevitable period of adjustment.

"The difference between bringing your own players in and inheriting players is that they were groomed under another manager and they’re set in the other manager’s ways.

“The existing Manchester United players certainly have the capacity to adjust successfully to working under Moyes and those players that he signs will be saying, 'This man trusts in me, he’s signing me for the mighty Man United, he must think I’m special', and that’s where I think that will make a difference.”